Steam safety-valve.



No. 794.034. PATENTED JULY 4, 1905. J. H. MILLETT & F. A. HANNAH.

STEAM SAFETY VALVE.

APPLICATION FILED DEO.19, 1904.

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.bnrnn %TATM@ Patented. Fullyl, 1905.

ll tltlllUA H. MllJLlCTT, OF ll'lrilillllfllll, AND FREDERICK it. HANNAH, OF

lrllCDFORD, .lrlASSACHUSETTS, AND VALVE CUitlPANY, OF TIUN OF MASSACHUSETTS.

ASSIGNOREB TO CROSBY tlTlTlEAlVI GAGE liOtdTON, ltlASSAUHUtSE. "re, A CORQPORA SPECIFICATION forming part of Letters Patent l lo. 79d,03t, dated July l, 1905. Application filed December 19, 1904. Serial No. 287,865.

Be it known that we, JosnUA H. ltlILl'JE'lT, residing at llllalden, and FREDERICK A. HAN- nnn, residing at Mcd'ford, in the county oi" llllirfldlesex and State of lllassachusctts, citizens of: the United States, have invented certain. new and useful improveiments in Steam. Safety-Valves, of which the following is a specification.

Our invention relates to steam salety valves, and is an improvement upon the invention described in the application for Letters Patent tiled by'us June 2S), 1004-, and now pending, Serial No. 214,692.

The improvement consists in certain novel features of construction, arrangement, and combination of parts and is illustrated by the acconmanying drawings, in which.-

l igure 1 is a vertical central section oil. a valve embodying our improvement. l? 2 is a plan view on the line 2 2, Fig. l.

l is a valve furnished with the base 2, in which is located the pop-chamber 3, with its outlets a controlled by the ring 5 in thread ed. engagement with the valve casing c and locked in place by the bolt 7. in the base 2 are located also the annular valve-seats r; and 5-), on, which is seated the valve proper, which we call the disk, 10. This disk constitutes the middle frustum of a sphere. The 'lrustum. oil a sphere any part of a s 'ihere comprised between two parallel sections, and the middle lrustum ol. a sphere is that lrustuin whose ends are cq ual circles. e extend the use. oil the term middle Frustum to include a trustuiin composed of the adjoining parts of the two hemispheres, though. these parts be not absolutely similar. This disk 10 we ar range in the cylinder 1. 1, which forms a guideway therefor and which is projected. from or forms the lower portion of the spring-chamber 12, which surmuruls the spring 1 2-3 and is liked to or preferably cast with the valve-casing 6. The disk 10 is held to its seat by the spring 13 and pintle 15, arranged between. said spring and disk.

The disk 10, having spherical sides, as described, canv rotate, but cannot wabble, tilt, cock, or bind. It always in circumferenti al linear contact with the cylinder inv a plane 17 parallel to that oil the alve-base. The cylinder 1] is preferably made 01' larger diameter than the spriiig-chamber 1.2, thereby forming an annular ilange 16, which limits the upward travel ol the disk and preserves the contact described. The disk thus an ranged and guided terms a movable bottom to the spri rig-chamber and prevents the steam. from reaching said chamber and also from collecting above the disk itself and creating an und. sirable back pressure.

In actual op oration in a valve properly constructed a disk of the relative size shmvn in. the d rawin will never rotate enough to force it against the flange at the top of the guidingcylinder.

:lll aving described our invention, what we claim, andv desire to secure by Letters Patent, is

1. In a safety-valve the combination, with the valve-easing, sprin and spring-ch amber, of a disk constituting the middle iirustum oil" a sphere and a guideway there'lbr in the form of a cylinder projectcdfrom said spri ng-ch am her, said disk forming the bottom oil. said spring-chaml)er and being held to its seat by said spring; substantially as described.

2. 111 a sat ety-valve the combination, with the valve-casing, spring and spring-eharnber, oi a disk eimstituting the middle ilrustum of a sphere, said spring-chmnber being extended to inclose said. disk and form a guideway therefor, said disk forming the bottom Oil said spring-chamber and being held to its seat by said spring; substantially as described.

in. testimony whereof we have hereto ailiixed our signatures in presence of two witnesses.

JOSHUA ll. ,lz'lllLLlCilTl. I REDIERI'UH It. HANNAH.

Witnesses lfinwann C. Barns, Rarrir l/V. liosrnn. 

